Basisc of pigging - Pipeline pigging refers to maintenance practice for pipelines using ‘pipeline pigs’, for cleaning or inspection of pipeline without stopping operation of the pipeline. Pipeline pigs are capsule shaped objects which travel through the pipeline, cleaning the inner walls of the pipeline by brushing action. Pigs get their name from the squealing sound they make while traveling through a pipeline.
Pig Traps (pig receivers and pig launchers) - Pig launchers are essentially vessels used for launching of a pipe pig or a pig tool into the pipeline for cleaning or inspection purpose. After being launched into the pipeline, the pig tool is pushed through the pipeline by a driving fluid. The pipeline is cleaned along the way by brushing action from the pig. On the other end the pig tool is received by a pig receiver.
Pipe Pig - Pipe pigs are capsule like objects used for cleaning of pipeline by pushing them through the pipeline using fluid pressure. The pipe is cleaned by brushing action from the pig tool. This cleaning process is called pipeline pigging. Pig tools are also used to separate different products in a multiproduct pipeline.
Typical P&ID arrangement for pig launchers and receivers - Typical arrangement for pig launchers and pig receivers used for oil pipelines is shown including the requirements for isolating, draining/venting and bypassing the pig traps. Other requirements such as balancing/kicker lines, purging connections, motorized valves, relief valves are also presented.
Typical Procedure for Pigging Operations - Hazards involved in the pigging operations, precautions to be taken during pigging and typical step by stem procedure for pigging is discussed. The procedures to be followed at pig launcher end and at pig receiver end are discussed.